Air actuated switch for intermittent sheet control



H. HOPE Oct. 3, 1967 5 Sheets-Sheet 1 Filed Feb. 15, 1966 Q? i-L INVENTOR HOPE ATTORNE Y Oct. 3, 1967 I HOPE 3,345,475

AIR ACTUATED SWITCH FOR INTERMIT'I'ENT SHEET CONTROL Filed Feb. l5, 1966 5 Shets-Sheet 2 INVENTOR. HENRY H I BY . ATTORNEY H. HOPE AIR ACTUATED SWITCH FOR INTERMITTENT SHEET CONTROL Filed Feb. 15, 1966 3 Sheets-Sheet 3 .INVENTOR.

United States Patent 3,345,475 AIR ACTUATED SWITCH FOR INTERMITTENT SHEET CONTROL Henry Hope, 195 Welsh Road, Huntingdon Valley, Pa. 19006 Filed Feb. 15, 1966, Ser. No. 527,689 7 Claims. (Cl. ZOO-61.13)

This invention relates to a control apparatus for intermittingly activating or de-activating a motor or other source of energy.

More particularly, this invention relates to means whereby the motor is activated and de-activated by an air pressure responsive control apparatus, the change in pressure being effected by the movement of a workpiece over a predetermined point.

One object of this invention is to provide an improved control apparatus of the type set forth.

A further object is to produce a control apparatus which is simple, foolproof, durable and inexpensive.

A still further object is to produce a control apparatus which is especially adaptable for use under conditions which do not permit the use of mechanical devices or the use of devices embodying light or heat.

A still further object is to provide an improved control apparatus which activates or de-activates a motor for intermittingly propelling X-ray negatives or other sheets from one location to another.

The full nature of the invention will be understood from the following specification and the accompanying drawings in which:

FIG. 1 is a top plan view of one embodiment of the invention.

FIG. 2 is a sectional view looking in the direction of line 22 on FIG. 1.

FIG. 3 is a sectional view looking in the direction of line 3-3 on FIG. 1.

FIG. 4 is a top plan view of a second embodiment of the invention, certain parts being cut away to show internal structures.

FIG. 5 .is a side elevated view of the same and shows the apparatus ready to receive a workpiece to be propelled.

FIG. 6 is similar to FIG. 5 and shows the apparatus in the process of propelling an X-ray film from one location to another.

FIG. 7 is a sectional view looking in the direction of line 7-7 on FIG. 5.

FIG. 8 is a sectional view looking in the direction of .wall 16. To the outside of chamber 12 is secured micro switch 19 by means of bracket 20, said switch including an actuating arm 21, to one end thereof is secured a door 22 which closes opening 25 in top 16 of chamber 12.

The control apparatus also includes nip rolls 28 and 30 which are driven constantly, by a motor, not shown, whereby an X-ray film 32 or the like, fed to said rolls .by motor M-1 will be propelled forwardly by said nip rolls as viewed in FIG. 1, or to the left as viewed in FIG. 2.

The operation is as follows:

When no workpiece is being propelled between nip rolls 28 and 30, the air entering chamber 12 flows freely out of said chamber through discharge slots 15. As long as said discharge slots are unobstructed, the pressure in chamber 12 is not enough to raise door 22 and switch arm 21, therefore switch 19 remains closed and the motor M-l which feeds the X-ray film to the nip rolls continues to run.

But, when the leading end of film 32 obstructs slots the air pressure within chamber 12 is increased to a value calculated to lift door 22 and, in so doing, to move switch arm 21 to its upper position in which switch 19 will be opened and film feeding motor M-l will be de-energized. It will be remembered however, that opening switch 19 does not affect rolls 28 and 30 which continue to be rotated.

As soon as the trailing end of the film has cleared discharged slots 15, air can again flow freely through said slots and the pressure in chamber 12 will decrease so as to permit door 22 and switch arm 21, to move to their lower position in which switch 19 is again closed and motor M-1 which actuates the mechanism which feeds films to the nip rolls will again be energized to deliver another film, and so on.

In the embodiment of FIGS. 4 to 8, blower housing 10', motor M, motor M-l, micro switch 19, bracket 20, switch arm 21, and door 22 are the same elements as those specified in FIGS. 1, 2 and 3. But, instead of discharge slots 15, I provide a pair of discharge nozzles 17 and 18 which are so located as to be obstructed by a film 32 emerging from nip rolls 23 and 24. Nozzles 17 and 18 are at the ends of two branches of a plenum 14, which is connected, through air pipe 13, to chamber 12', which corresponds to chamber 12. To position nozzles 17 and 18 close to and under the nip rolls, lower roll 24 is notched as at 26.

The operation of the second embodiment is the same in principle as that of the first embodiment, the only difference being that the nozzles and the nip rolls are located at a distance from the air chamber and the switch. This arrangement is advantageous when the workpiece must be separated from the switch and/ or chamber for reasons of size or safety. For example, if the workpiece contains explosive or volatile material, the switch must be kept a safe distance from said workpiece.

Nozzles 17 and 18 or discharge slots 15 can be obstructed by a single film which is wide enough to span both nozzles or slots or by two films propelled in tandem. In the event a single film not wide enough to obstruct both nozzles or slots is being processed, one nozzle or slot may .be obstructed by a plate or other means, and said film as it passes over the other slot or nozzle will actuate the switch.

It should be noticed that, as a film 32 passes over discharge slots 15 or nozzles 17 and 18, a layer of air forms beneath the film as seen in FIG. 8. This layer of air acts as a support cushion for the film and tends to support the leading end of the film pending its engagement with take up rolls, not shown, which propel the film into a developing tank or to storage, and so on.

What I claim is:

1. An air pressure operated switch for controlling a source of energy, said switch comprising:

a fixed contact,

a movable contact normally out of engagement with said fixed contact,

an electric circuit including said contacts,

a chamber,

means for delivering air under pressure into said chamher,

an opening leading from said chamber to the atmosphere,

a door for said opening,

and a switch arm secured at one end thereof to said door and secured at the other end thereof to said movable contact,

said door being so constructed and arranged that, in

the absence of pressure in said chamber of a predetermined value, said door obstructs said opening and moves said arm to switch closing position and 3 so that, when the pressure in said chamber reaches said predetermined value, said door moves to an unobstructing position and moves said arm to switch opening position,

said chamber having a second normally unobstructed opening leading to the atmosphere,

said second opening being adapted to be obstructed by a workpiece passing thereover to raise the pressure within said chamber to said predetermined value.

2. Incombination:

a chamber having a first and a second opening leading to the atmosphere,

a door normally closing said first opening,

a feed mechanism for propel-ling a workpiece over said second opening to obstruct the same,

a motor for delivering successive workpieces to said feed mechanism,

a switch for energizing said motor,

a switch arm connected to said door and said switch,

said switch arm being arranged to close said switch to energize said motor when said door is closed and to open said switch to de-energize 'said motor when said door is opened, and

means for delivering air under pressure to said chamber,

said door being so arranged as to close said first openopening as long as the pressure within said chamber is less than a predetermined value and to open said door when the pressure is greater than said prede termined value.

3. The device defined in claim 2 wherein said second opening is remote from said chamber and a conduit connecting said chamber and said nozzle.

4. The device defined in claim 2 wherein said second opening is located in the same wall as said first opening.

5. An apparatus for controlling the delivery of an X-ray film or the like including:

a chamber having first, second and third openings leading to the atmosphere,

said first opening being located near one end of a wall of said chamber,

said second and third openings being located in said wall and spaced from said first opening and from each other,

a door normally closing isaid first opening,

a feed mechanism for selectively propelling workpieces over .said second and third openings to obstruct the same,

a motor for delivering successive workpieces to said feed mechanism,

a switch for energizing said motor,

a switch arm connected to said door and said switch,

said switch arm being arranged to close said switch to energize said motor when said door is closed and to open said switch to de-energize said motor when said door is opened,

means for delivering air under pressure to said chamber, said door being so arranged as to close said first opening as long as the pressure within said chamber is less than a predetermined value and to open said door when the pressure is greater than said predetermined .Value, whereby the obstruction of said second and third openings by a workpiece raises the pressure within said chamber beyond said predetermined value and opens said door and said switch to de-energize said motor.

6. In combination with a mechanism comprising a motor for propelling a sheet from one site to another, an air pressure operated switch for energizing and deenergizing .said motor according to the presence, or absence, of a film in said mechanism, said air switch including:

a fixed contact,

a movable contact, movable to a first position in which it engages said fixed contact and energizes said motor, and to a second position in which it .does not engage said fixed contact, and said motor is deenergized,

said movable arm normally occupying said second position,

actuating means responsive to air pressure of a predetermined value to move said movable contact to its second position,

a source of air under pressure of a pre-determined value,

a plenum having two spaced openings leading to the atmosphere,

conduit means for connecting said plenum through at least one of said openings, with said source of air,

Said openings being disposed in the path of movement of, and being adapted to be at least partially obstructed by a moving film whereby at least partial obstruction of either of said openings by a portion of said film lowers the air pressure exerted on said actuating means to a point below said predetermined value and permits return of said movable contact to its second position.

7. The apparatus defined in claim 6 wherein said film moves substantially horizontally and said openings are below said film, whereby the air flowing out of said openings at least partially supports said film.

References Cited UNITED STATES PATENTS 2,274,269 2/1942 Hercik ZOO-461.18 X 2,800,283 7/1957 Weber etal. ZOO-61.86 X 3,178,527 4/1965 Cooksey 20061 .13 X 3,185,784 5/1965 Geiger et al. 20061.18

BERNARD A. GILHEANY, Primary Examiner.

R. N. ENVALL, JR., Assistant Examiner. 

1. AN AIR PRESSURE OPERATED SWITCH FOR CONTROLLING A SOURCE OF ENERGY, SAID SWITCH COMPRISING: A FIXED CONTACT, A MOVABLE CONTACT NORMALLY OUT OF ENGAGEMENT WITH SAID FIXED CONTACT, AN ELECTRIC CIRCUIT INCLUDING SAID CONTACTS, A CHAMBER, MEANS FOR DELIVERING AIR UNDER PRESSURE INTO SAID CHAMBER, AN OPENING LEADING FROM SAID CHAMBER TO THE ATMOSPHERE, A DOOR FOR SAID OPENING, AND A SWITCH ARM SECURED AT ONE END THEREOF TO SAID DOOR AND SECURED AT THE OTHER END THEREOF TO SAID MOVABLE CONTACT, SAID DOOR BEING SO CONSTRUCTED AND ARRANGED THAT, IN THE ABSENCE OF PRESSURE IN SAID CHAMBER OF A PERDETERMINED VALUE, SAID DOOR OBSTRUCTS SAID OPENING AND MOVES SAID ARM TO SWITCH CLOSING POSITION AND SO THAT, WHEN THE PRESSURE IN SAID CHAMBER REACHES SAID PREDETERMINED VALUE, SAID DOOR MOVES TO AN UNOBSTRUCTING POSITION AND MOVES SAID ARM TO SWITCH OPENING POSITION, SAID CHAMBER HAVING A SECOND NORMALLY UNOBSTRUCTED OPENING LEADING TO THE ATMOSPHERE, SAID SECOND OPENING BEING ADAPTED TO BE OBSTRUCTED BY A WORKPIECE PASSING THEREOVER TO RAISE THE PRESSURE WITHIN SAID CHAMBER TO SAID PREDETERMINED VALUE. 